Why does Plasma occasionally replace Thunderbird's logo with Firefox's?

Examples

My Environment

  • fastfetch -l none returns:

    OS: Fedora Linux 43 (KDE Plasma Desktop Edition) x86_64
    Host: Laptop 16 (AMD Ryzen 7040 Series) (A7)
    DE: KDE Plasma 6.5.3
    WM: KWin (Wayland)
    WM Theme: Breeze
    Theme: Breeze (Dark) [Qt], Breeze [GTK3/4]
    Icons: breeze-dark [Qt], breeze-dark [GTK3/4]
    
  • kinfo returns:

    KDE Frameworks Version: 6.20.0
    Qt Version: 6.10.1
    Kernel Version: 6.17.9-300.fc43.x86_64 (64-bit)
    Graphics Platform: Wayland